Combination Bulk Carriers

Abstract

This paper is a state-of-the-art report on bulk carriers that carry both dry and liquid cargoes. There were approximately 96 vessels of this type in service in April 1966 and almost 50 others were building or contracted for at that time. All available characteristics of these vessels are tabulated in an Appendix and numerous sketches showing various designs are included. Hull proportions, cubic capacity versus deadweight ratios, ballast capacities, and structural arrangements of various types are compared. Freeboard assignment, Classification Society requirements, tonnage admeasurement, and Panama and Suez Canal requirements and restrictions are discussed. The use of various cargo spaces for both dry and liquid cargoes, changeover considerations, and associated problems of cleaning, cargo heating, ventilation, and ballasting are reviewed. Construction and operating costs are considered and some comparisons made with straight bulk carriers. The paper emphasizes the payload percentage of sea time and the ability of switching from a dry to a liquid cargo, or vice versa, as strong reasons for the growing popularity of this type.